Bluish-red disazo dye.



- dition 0 AUGUST LEOPOLD LASKA, OF OFFENBACH-ON-THE-MAIN, GERMANY,ASSIG-NOR '10 CORPORATION CHEMISCHE FABRIK GRIESI-IEIM-ELEKTRON,

THE-Mun, GERMANY.

OF FRANKFURT-ON- BLUISH-RED DISAZO DYE.

No Drawing. I

Specification of Letters Patent.

Application filed April 13, 1910. Serial No. 555,283.

Patented July 19, 1910.

To all whom it may concern:

Be it known that I, AUGUST LEOPOLD LAsKA, doctor of philosophy, chemist,a subject of the German Emperor, and resident of Offenbach-on-the-Main,in the Grand Duchy of Hesse, Germany, with the post-office addressGerberstrasse 5, have invented new and useful Improvements in Bluish-RedDisazo Dyestuffs, of which the following is a specification.

My invention relates to the production of disazo dyestuffs, which may beused advantageously for the preparation of color lakes.

The process consists in combining the tetrazo compounds ofdichlorodiaminodiphenolalkylethers having the formula:

ox ox NH,

ol 01 wherein X means an alkyl group, with two molecules beta-naphthol.The thus obtained disazo dyestuffs can be transformed in bluish-redcolor lakes being very fast against light and insoluble in water andoil. Among alkylethers of, the dichlorodiaminodiphenol may be used forinstance dichlorodianisidin and dichlorodiphenetidin. The transformationof the dyestufis in pigment colors can be performed in the usual manner.Of course the combination of the tetrazo compounds with beta-naphtholcan be made also in presence of a substratum. Example: 15.6 parts ofdichlorodianisidin are diazotized by means of 6.9 parts of sodiumnitrite and the necessary quantity of hydrochloric acid. The resultingsolution, which if necessary may be filtered, is introduced into an icecold solution of 16 parts of beta-naphthol in 14 parts of caustic sodalye (35 B.) and 250 parts of water containing 6 arts of soda.Theentirely preci itated yestufl is filtered off, washed and ad vantaeously used in asty form. An ad- Turkey red o'r or a similar actingingredient, for instance soap, to the solution of beta-naphthol isrecommendable. The dyestufi' forms in dry state a dark-red powder,insoluble in water, soluble in concentrated sulfuric acid with bluecolor. By reduction with stannous chlorid and hydrochloric acid thedyestufl is split in dichlorodianisidin and aminona hthol.

Now what I claim an desire to secure by Letters Patent is the following:

1. The process for the production of disazo dyestufi's, consisting incombining the tetrazo compounds of dichlorodiaminodiphenolal kylethersof the aforesaid constitution with two molecules ofbeta-naphthol.

2. As new articles the disazo dyestuffs obtained by combination oftetrazo compounds of dichlorodiaminodiphenolalkylethers of the aforesaidconstitution with two molecules of beta-naphthol, which dyestuffs formin dry state dark-red powders, insoluble in water, soluble inconcentrated sulfuric acid with blue color, and which by reduction withstannous chlorid and hydrochloric acid are split indichlorodiaminodiphenolalkylethers and aminonaphthol.

8. The process for the production of a disazo dyestufl, consisting incombining the tetrazo compound of dichlorodianisidin with two moleculesof beta-naphthol.

4. As a new article the dyestufl obtained by combination of thetetrazo-compound of dichlorodianisidin having the aforesaid constitutionwith two molecules of beta-naphthol, which dyestuif forms in dry state adark-red powder, insoluble in water, soluble in concentrated sulfuricacid with blue, and splitting by reduction with stannous chloridand'hydrochloric acid in dichlorodianisidin and aminonaphthol.

In testimony, that I claim the foregoing as my invention, I have signedmy name in presence of two witnesses, this second day of April 1910.

AUGUST LEOPOLD LASKA.

Witnesses:

HERMANN VVERT, KATHINKA PFEIFFER.

